Behavioural responses of the Round Goby, Neogobius melanostomus, to signals from conspecifics

There are several modalities through which fish can communicate, but oftentimes they rely primarily on chemical and visual signaling. The Round Goby (Neogobius melanostomus) is a prolific invader of the Laurentian Great Lakes. My goal was to examine the behavioural responses of this species to signals from conspecifics. Using behavioural assays, I found that visual signals (i.e. nuptial colouration) rather than chemical signals (i.e. urine) from males were attractive to reproductive females. I also examine the attraction of juveniles to eggs odours; individuals significantly preferred conspecific to heterospecific odours. Lastly, I compare the allometric relationships between pectoral fins and body length in males and females, which may contribute to the reproductive success of an individual. My research improves our understanding of the behavioural ecology of an invasive species of fish

Latimerija - živi fosil

This study, which derives from work initiated as part of a N.A.T.O. Collaborative Linkage Grant (LST‐CLG No. 979499), supported by consecutive research contracts (SF0238 and SF0248) from the UK Department of Environment, Food and Rural Affairs (to GHC), which were complemented by a Marie Curie postdoctoral fellowship (PIEF‐GA‐2008‐219707) and a subsequent research grant from the National Science Centre, Poland (decision No DEC‐2011/01/D/NZ8/01807) to GZ.Carotenoid‐based pigmentation is a striking feature of many taxa, yet the function, if any, of colour traits is often unclear. Pumpkinseed Lepomis gibbosus, a widely introduced freshwater sunfish that exhibits alternative male mating strategies, express a striking, red operculum spot. To investigate the potential function of this red spot as a signal in this species' mating system, we determined the presence and measured the size of red operculum spots in fish collected from 12 populations in five European countries in which pumpkinseed is an established non‐native species. We subsequently related the presence and size of the red spot to body size and mating strategy, based on an analysis of relative gonad size (gonado‐somatic index, GSI), using a mixed modelling approach. The study demonstrated that the presence of a red operculum spot in pumpkinseed is associated with sexual maturation, with GSI frequency distributions suggesting that cuckolders in some non‐native populations comprised both sneaker and satellite males, the latter not having previously been reported for this species. Further, the size of red spot correlated strongly with body size in parental and cuckolder males, although there was no difference in the presence or size of the red operculum spot between male mating strategies. The function of a red operculum spot in females is not clear but may be partly mediated by pleiotropic genetic mechanisms. Red operculum spots appear to function as signals of male maturation and body size in pumpkinseed, irrespective of mating strategy.PostprintPeer reviewe

Yavno_Fox_DATA

Raw morphological measurements of traits associated with both the traditional centroid, and swimming. Trait names are listed at the top of each column; population and water treatment are listed in the first two columns

Data from: Morphological change and phenotypic plasticity in native and non–native pumpkinseed sunfish in response to sustained water velocities

Phenotypic plasticity can contribute to the proliferation and invasion success of nonindigenous species by promoting phenotypic changes that increase fitness, facilitate range expansion and improve survival. In this study, differences in phenotypic plasticity were investigated using young-of-year pumpkinseed sunfish from colonies established with lentic and lotic populations originating in Canada (native) and Spain (non-native). Individuals were subjected to static and flowing water treatments for 80 days. Inter- and intra-population differences were tested using ancova and discriminant function analysis, and differences in phenotypic plasticity were tested through a manova of discriminant function scores. Differences between Iberian and North American populations were observed in dorsal fin length, pectoral fin position and caudal peduncle length. Phenotypic plasticity had less influence on morphology than genetic factors, regardless of population origin. Contrary to predictions, Iberian pumpkinseed exhibited lower levels of phenotypic plasticity than native populations, suggesting that canalization may have occurred in the non-native populations during the processes of introduction and range expansion

Morphological change and phenotypic plasticity in response to water velocity in three species of Centrarchidae

Morphological responses to flowing water have been documented in many fishes, but rarely reported in species with gibbose body types, despite their use of riffles in rivers and streams. In this study, we compared morphological responses to water flow in three gibbose centrarchids; the bluegill Lepomis macrochirus (Rafinesque, 1819), pumpkinseed Lepomis gibbosus (L., 1758), and rock bass Ambloplites rupestris (Rafinesque, 1817). Flow-through plexiglass units, set to either a sustained flow or static conditions, were used to rear juveniles from each species for an 80-day period. All three species developed more streamlined body forms, longer and thinner caudal peduncles and longer pectoral fins when reared in sustained current. The pumpkinseed exhibited the highest level of phenotypic plasticity in response to water flow, followed closely by bluegill; rock bass was the least plastic species. Rock bass developed longer pre-dorsal and pre-pectoral lengths, which differ from the morphological changes observed in the bluegill and pumpkinseed. The findings not only suggest that some gibbose fishes are capable of exhibiting strong phenotypic responses to water flow, but that many morphological changes are species specific, even within the same taxonomic family. Lastly, all three species developed shorter dorsal fin base lengths when reared under flowing condition, which differs from some previously documented work on fusiform fishes. The results of this study provide a better understanding of how morphology in three closely related species varies in response to environmental conditions.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Red operculum spots, body size, maturation and evidence for a satellite male phenotype in non-native European populations of pumpkinseed Lepomis gibbosus

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Red operculum spots, body size, maturation and evidence for a satellite male phenotype in non-native European populations of pumpkinseed <i>Lepomis gibbosus</i>

Carotenoid‐based pigmentation is a striking feature of many taxa, yet the function, if any, of colour traits is often unclear. Pumpkinseed Lepomis gibbosus, a widely introduced freshwater sunfish that exhibits alternative male mating strategies, express a striking, red operculum spot. To investigate the potential function of this red spot as a signal in this species' mating system, we determined the presence and measured the size of red operculum spots in fish collected from 12 populations in five European countries in which pumpkinseed is an established non‐native species. We subsequently related the presence and size of the red spot to body size and mating strategy, based on an analysis of relative gonad size (gonado‐somatic index, GSI), using a mixed modelling approach. The study demonstrated that the presence of a red operculum spot in pumpkinseed is associated with sexual maturation, with GSI frequency distributions suggesting that cuckolders in some non‐native populations comprised both sneaker and satellite males, the latter not having previously been reported for this species. Further, the size of red spot correlated strongly with body size in parental and cuckolder males, although there was no difference in the presence or size of the red operculum spot between male mating strategies. The function of a red operculum spot in females is not clear but may be partly mediated by pleiotropic genetic mechanisms. Red operculum spots appear to function as signals of male maturation and body size in pumpkinseed, irrespective of mating strategy